An important line of research within empirical aesthetics has been to determine how specific physical features, such as complexity, influence art preference. Researchers have hypothesized that art preference follows an inverted-U function of complexity, in that people tend to like art with increasing visual complexity up to a certain level, at which point preferences drop. However, what determines the peak complexity of the inverted-U function remains unknown. Here, we demonstrate that the inverted-U relationship depends on visual-object working memory (VOWM). Participants rated the complexity of 120 images of fine art in three blocks of presentations: upside-down for 50 ms, upright for 500 ms, and upright self-paced. We reasoned that viewing 50-ms upside-down images would provide minimal content information encouraging participants to judge visual complexity, whereas viewing 500-ms or self-paced upright images allowed participants to consider semantic factors in the complexity judgment. Participants subsequently rated all images on aesthetic preference. At the end of the experiment, VOWM and verbal working memory (VWM) were assessed in separate n-back tasks; VOWM was measured using pictures consisting of random 4-by-3 arrangements of gray-scale squares, and VWM was measured using words. We found that VOWM, but not VWM, correlated with preference for complexity in art. Individuals with higher VOWM preferred complex art more and simple art less, with the most preferred level of complexity elevated in individuals with higher VOWM. Importantly, these relationships were obtained only for the complexity ratings on the 50-ms upside-down images, but not for complexity ratings on the 500-ms or self-paced upright images, indicating that VOWM influences aesthetic appreciation of visual complexity (i.e., not semantic complexity). Specific visual features that promote art preference have been previously identified, but our result highlights the idea that influences of these features are systematically modulated by individual variations in visual-object working memory capacity.